> For the complete documentation index, see [llms.txt](https://yams.yassrobotics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yams.yassrobotics.com/documentation/tutorials/swerve-drive.md).

# Swerve Drive

Learn how to program a Swerve Drive.

{% hint style="danger" %}
Swerve drive requires more hardware configuration than a tank drive. Make sure you have installed YAMS, REVLib (for the `SparkMax` motor controllers) and Phoenix 6 (for the `CANcoder`s and the `Pigeon2`) before starting. [Create a project and install YAMS](/documentation/tutorials/project-setup.md) walks through it.
{% endhint %}

## Intro

This tutorial builds a swerve drive that works in real life and simulation with the same code.

<figure><img src="https://1354553280-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZM0CFmYiQzcrY4zDcTtZ%2Fuploads%2Fgit-blob-8314f33fa57f8b964ff714ce3dd6c1f50bb70505%2Ftutorial-swerve-modules.gif?alt=media" alt="Animation of two controller sticks and a top view of a swerve drive with its four modules. Left stick forward: every module points forward at the same speed. Left stick left: every module turns to point left and the robot does not rotate. Right stick left: the modules form a circle and the robot spins in place. Both sticks: each module gets its own angle and speed."><figcaption><p>You ask for a chassis speed. <code>SwerveDrive</code> works out the four modules.</p></figcaption></figure>

## Details

This swerve drive uses the following hardware and controls:

* 4x `SparkMax` (NEO) drive motors, CAN IDs 1, 4, 7, 10
* 4x `SparkMax` (NEO) azimuth motors, CAN IDs 2, 5, 8, 11
* 4x `CANcoder` absolute encoders, CAN IDs 3, 6, 9, 12
* `Pigeon2` gyro, CAN ID 14
* Drive gear ratio `12.75:1`, azimuth gear ratio `6.75:1`, 4 inch wheels
* The left stick translates, and the right stick's X axis rotates
* Holding the left bumper drives to a pose on the field

{% hint style="warning" %}
**Simulation Processing Requirements**: YAMS simulates **each motor individually**. With 4 modules containing 2 motors each, that is 8 `SmartMotorController` instances running physics simulation simultaneously. This provides highly accurate simulation but requires more processing power than simplified kinematic-only simulations.
{% endhint %}

## The steps

<figure><img src="https://1354553280-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FZM0CFmYiQzcrY4zDcTtZ%2Fuploads%2Fgit-blob-4d6d7e3aeadd15082c70ba3fdabcffe9552eee3a%2Ftutorial-swerve-steps.png?alt=media" alt="The three steps of the swerve drive tutorial. Step 1, the module motors: a config for the drive motors and a config for the azimuth motors. Step 2, the modules and the drive: four SwerveModules, a gyro and a SwerveDrive. Step 3, driving: drive commands, and a SwerveInputStream that reads the controller."><figcaption><p>Three steps, one page each.</p></figcaption></figure>

Every step has a tab for **Java with Commands v2**, **Java with Commands v3** and **C++**.

| Step                                                                                            | What you do                                                                                              |
| ----------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| [Before you start](/documentation/tutorials/project-setup.md)                                   | Create a WPILib project and install YAMS, REVLib and Phoenix 6. Skip this if you already have a project. |
| [Step 1: The module motors](/documentation/tutorials/swerve-drive/module-motors.md)             | A config for the drive motors and a config for the azimuth motors.                                       |
| [Step 2: The modules and the drive](/documentation/tutorials/swerve-drive/modules-and-drive.md) | Build four `SwerveModule`s, add the gyro, and create the `SwerveDrive`.                                  |
| [Step 3: Driving](/documentation/tutorials/swerve-drive/driving.md)                             | Drive commands, a `SwerveInputStream` for the sticks, and the bindings.                                  |

## Complete example

The following files from the YAMS `simple_robot-2027` Commands v2 example show a complete swerve drive implementation matching the hardware described in this tutorial.

{% @github-files/github-code-block url="<https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/commands2/simple_robot-2027/src/main/java/first/robot/subsystems/SwerveSubsystem.java>" %}

{% @github-files/github-code-block url="<https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/commands2/simple_robot-2027/src/main/java/first/robot/RobotContainer.java>" %}

The same drive in the other two flavors:

* **Java, Commands v3:** [`SwerveMechanism.java`](https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/commands3/simple_robot-2027/src/main/java/first/robot/mechanisms/SwerveMechanism.java) in `examples/commands3/simple_robot-2027`
* **C++:** [`SwerveSubsystem.h`](https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/cpptest/src/main/include/subsystems/SwerveSubsystem.h) and [`SwerveSubsystem.cpp`](https://github.com/Yet-Another-Software-Suite/YAMS/blob/master/examples/cpptest/src/main/cpp/subsystems/SwerveSubsystem.cpp) in `examples/cpptest`

## Next steps

* Learn about [AdvantageKit Integration](/documentation/understanding/advantagekit-integration.md) for swerve
* See [Organizing Configs in Constants](/documentation/understanding/config-organization.md) for cleaner code
* Record this drive's telemetry to a file and review it after a match, see [How do I view my DataLog in AdvantageScope?](/documentation/how-to-simulation-and-logging/how-do-i-view-my-datalog-in-advantagescope.md)